1. FIELD OF THE INVENTION
The present invention relates to self-locking nut fasteners.
2. DESCRIPTION OF RELATED ART
When using nut and bolt fasteners it is generally desirable to have means to prevent the nut from loosening due to vibration, thermal expansion, etc. Typically this is done by placing a lock washer between the nut and the working surface to maintain bolt tension in the joint. Having to use a separate washer is cumbersome particularly when the nut is being used in places with limited accessibility. There are also assemblies where there is not enough space between the nut and workpiece for a lock washer. Prior attempts to incorporate a locking feature into the nut itself include U.S. Pat. No. 4,269,248 issued to MacLean et al, which discloses a fastener that has a wavy flange at one end that deforms when the nut is tightened, keeping the bolt in tension. U.S. Pat. No. 2,286,895 issued to Carlson discloses a lock nut that has a locking portion that bends when the fastener engages a working surface. The locking portion clamps against an adjacent thread of the bolt increasing the frictional forces between the nut and the bolt. Although these fasteners provide a locking feature, there has not been to this point a nut that is self-locking at both ends of the nut.